Core Web Vitals

Core Web Vitals turn "the page feels slow" into three measurable numbers: loading (LCP), visual stability (CLS), and responsiveness (INP). They're a ranking factor, but a tie-breaker one — great vitals won't rescue weak content, and Google uses real Chrome user data (field data), not just lab tests, to score you. Passing all three across most page views is the practical target, and mobile scores usually lag desktop, so optimize there first.